Roller derby, filthy puppets and more at Summer Repertory Theater

"The muses are in retreat!" warns the great god Zeus. "Creativity shall remain stymied for decades. The theater? They'll just take some stinkeroo movie or some songwriter's catalogue, throw it onstage and call it a show!"

There you have it. That pithy observation is one of the slyest and funniest lines in Summer Repertory Theater's current production of the delightfully silly musical Xanadu. Considering that Xanadu—with a fluffy-hearted book by Douglas Carter Beane—is adapted from one of the worst movies ever made, a film so bad it killed the rising film career of Olivia Newton-John, it's a bit of a shock that it's such an enjoyable, glittery, ridiculous pleasure.

The plot, a supercharged variation of the static original, involves the legendary muses, the daughters of Zeus, one of which comes to Earth to inspire a surfer-dude artist, ends up falling in love with him and breaks the rules by starting to create art herself. Her art project, in this case, is a roller disco palace called Xanadu. It's all pretty silly, but the music, including a few extra songs from Electric Light Orchestra's greatest hits (and one or two Newton-John hits as well), is infectious and fun, on or off roller skates.

The cast is strong and committed, showcasing some fine singers, though there are one or two performers who struggle to sing but excel in dancing. That's part of what happens with SRT, where participants are pushed to learn new skills in a theatrical boot-camp environment.

Xanadu is just one of five SRT shows running in repertory through August, along with Agatha Christie's Mouse Trap, Neil Simon's Sweet Charity, Sarah Ruhl's Passion Play and the multiple-award-winning musical Avenue Q.

Inspired by the offbeat multicultural neighborhood of Sesame Street, the cleverly kitschy Avenue Q—with a book by Jeff Whitty and music by Jeff Marx and Robert Lopez—combines live actors and furry puppet characters reminiscent of Bert, Ernie and the Cookie Monster. Alternately coarse and cuddly, the show is a wildly funny examination of modern life. For all of its warm-and-fuzzy look—and you can take fuzzy as literally as you like—Avenue Q pushes the envelope, challenging us to look hard, and to laugh hard, at the way we behave when different types of people are thrown together into neighborhoods and communities and forced to confront their own prejudices, preconceptions and assumptions.

If that sounds heavy, it doesn't come off that way onstage. This is one funny show, brilliantly performed by a cast up to its challenges. Featuring songs like "Everyone's a Little Bit Racist," "If You Were Gay" and "The Internet Is for Porn," Avenue Q is fresh, frisky and fun, but—furry puppets aside—definitely not for kids.

Less approachable, but equally bold a choice, is Sarah Ruhl's marathon-length Passion Play. Ruhl, whose fondness for experimental theater has defined her career, premiered this philosophical triptych just two years ago. Essentially three hour-long one-acts, each segment takes place in a different era and different country, beginning in Elizabethan England, moving to Nazi-era Germany, then to South Dakota in the 1960s. In each portion, the people of the community are preparing a presentation of the Passion Play, an age-old theatrical recreation of the death of Jesus.

Less about religion than about the power of theater and the way different people relate to iconic characters like Jesus, Pontius Pilate, the Queen of England and Adolf Hitler, it's a dense and baffling play, to say the least. But the large, versatile cast does what it can to bring spice and energy to the proceedings.

Summer Repertory Theater runs through Aug. 11, with shows every day except Monday, at various theaters at SRJC. 1501 Mendocino Ave., Santa Rosa. For full schedule of shows, times and prices, see www.summerrep.com.